Nepedia
Back to Discover
Advanced Reader
🧬

Overweight

life science Maturity 9-11 Next article →

Being overweight is defined as having more body fat than is considered healthy. While fat is necessary for the body to function, having too much stored fat can cause issues. Fat provides thermal insulation to keep us warm. It also acts as shock absorption for sensitive body parts. Additionally, fat supports the hormonal, reproductive, and immune systems. It even stores energy for future use. However, excessive fat accumulation can impair a person's movement and flexibility.

Overweight teenage boy (side)
Overweight teenage boy (side)

To track weight, researchers often use the Body Mass Index, or BMI. This is a calculation where a person's weight in kilograms is divided by the square of their height in meters. The results are written as kg/m2, though the units are usually left out. A BMI between 25.0 and 29.9 is classified as overweight. This range is sometimes called pre-obesity. If the BMI reaches 30.0 or higher, the person is classified as obese. BMI is a common tool because it is more accurate than simple weighing. However, it does not perfectly measure body fat percentage or mass. It may not account for factors like pregnancy or bodybuilding.

Scientists use several other methods to measure adiposity, which is the amount of fat in the body. One method is skinfold calipers, which involve a professional pinching the skin at specific points. This measures the thickness of fat layers just under the skin. Another method is bioelectrical impedance analysis. This passes a small electric current through the body. Because fat and muscle conduct electricity differently, this can estimate body fat percentage. Hydrostatic weighing is another highly accurate method. It involves submerging a person in water to compare their weight in water to their "dry weight." This helps determine body density, as fat is less dense than muscle.

Share of men defined as overweight, World, 2022 (cropped)
Share of men defined as overweight, World, 2022 (cropped)

Advanced technology allows for even more precise measurements. Dual-energy X-ray absorptiometry, or DEXA, uses density to identify fat in different body tissues. It was originally made to measure bone density. Another modern tool is the Body Volume Index, or BVI. Created in 2000, BVI uses 3D software to create an accurate image of a person. Unlike BMI, BVI can differentiate between different body shapes. It focuses on where weight is located, specifically looking at central obesity around the abdomen. This is important because abdominal fat is linked to greater health risks.

Weight classifications can change based on a person's ethnicity. The World Health Organization (WHO) and the NIH use a BMI of 25 for whites, Hispanics, and blacks. However, for Asians, the overweight range starts at a BMI of 23. These definitions help medical professionals assess risks accurately. Globally, the number of people in these categories is rising. In 2013, more than 2 billion adults were considered overweight or obese. By 2016, the WHO estimated nearly 2 billion adults were overweight. These increases are being observed across all age groups.

Being overweight can lead to various health challenges. It directly increases the risk of type-II diabetes. It is also identified as a risk factor for certain cancers. In men, it can increase the risk of oligospermia and azoospermia. Mental health is also a factor. Overweight individuals may face social discrimination. This can lead to risks for depression, panic disorder, or bipolar disorder. Interestingly, some research suggests different outcomes for certain groups. A 2016 review suggested a 7% increase in death risk for a BMI of 25 to 27.5. However, other researchers, like Katherine Flegal, found that mortality might actually be lower for those in the overweight category compared to the "ideal" weight range. In older populations, such as 70 to 75-year-old Australians, mortality was lowest among those classified as overweight.

Weight changes usually happen due to an imbalance of energy. This occurs when a person takes in more calories through eating than they expend through activity. Many factors can contribute to this, such as genetic predisposition or hormonal imbalances like hypothyroidism. A sedentary lifestyle and poor nutrition are also common causes. Other factors include insufficient sleep, stress, or certain medications like olanzapine. Even metabolic disorders caused by "weight cycling" can play a role. To manage weight, doctors often suggest diet and exercise. Dietitians may recommend balanced meals throughout the day. Some people also use support groups like Overeaters Anonymous or medical treatments like GLP-1 receptor agonists.

721 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (2)
File:Overweight teenage boy (side).jpg
Overweight teenage boy (side).jpg
File:Share of men defined as overweight, World, 2022 (cropped).svg
Share of men defined as overweight,...
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.